This comparative case study explores why two cities similar in socio-economic factors diverge in their pathways to environmental improvement. Our research looks at the changing local economies and environmental pollution problems facing Kitakyushu in Japan and Pohang in South Korea. Both cities drove their nations’ rapid economic growth as the main heavy industry hubs but have performed radically differently vis-à-vis public demands for environmental improvement despite sharing much in common. Employing the advocacy coalition framework as a main analytical tool, we examine the unfolding of policy efforts to turn a manufacturing-oriented industrial city into a “greener” city responding to environmental objectives and the respective outcomes. The research reveals that variations in regulatory decentralization, external events and coalition opportunity structures largely explain the observed discrepancy in green transition between the two settings. Our findings contribute to expanding scarce case study literature illustrating the mechanisms that can underpin environmental improvements in cities that have served as the location of heavy industries and offer suggestions for advancing them.

No abstract